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Bundle Branch Blocks, Emergency Medicine

Reviewed 06/2017



  • Blockage of intraventricular electrical impulses through the right and left bundles

  • Complete bundle branch block:

    • Absence or delay of conduction down one bundle, with normal conduction...


Signs and Symptoms

  • Asymptomatic

  • RBBB: Split S2 that persists with expiration

  • LBBB: Reversed/paradoxical split S2

  • Syncope

  • Chest pain

Essential Workup

  • RBBB:

    • Complete: QRS complex ≥0.12 sec

    • Incompl...



  • Monitor: Difficult to diagnose from single lead

  • Avoid confusing with ventricular tachycardia or ischemia, use.

  • Treat patient; bundle branch block requires no specific the...



Admission Criteria

  • Suspected myocardial ischemia

  • Syncope

  • Dysrhythmias

  • Bundle branch block with high-degree atrioventricular block

Discharge Criteria

Asymptomatic or incidental finding o...

Pearls and Pitfalls

  • Myocardial ischemia should be considered in all patients who develop new conduction abnormalities.

  • Specific criteria can be used to diagnose cardiac ischemia in patients with a bund...

Additional Reading

  • Brugada  J, Brugada  R, Brugada  P. Right bundle-branch block and ST-segment elevation in leads V1 through V3: A marker for sudden death in patients without demonstrable structural ...



  • 426.3 Other left bundle branch block

  • 426.4 Right bundle branch block

  • 426.50 Bundle branch block, unspecified

  • 426.53 Other bilateral bundle branch block

  • 426.2 Left bundle branch hemiblock

  • 426.51 R...

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